The present invention relates to a lever switch for vehicle installed near a steering wheel of an automobile, and a complex switch using the same.
A lever switch for vehicle is mainly used for changing over the functions of
1) headlight,
2) turn signal for direction indication,
3) wiper motor for operating the wiper of windshield or rear window, and
4) washer motor for ejecting washer liquid to the windowpane.
Each contact of the lever switch is connected to an electronic control circuit of the vehicle mounting a microcomputer for controlling them. The contacts of the lever switch are directly connected to the microcomputer. However, considering the possibility of malfunction of the microcomputer, the contacts for changing over the HI operation of the wiper motor and the headlight are also connected to the individual relays for driving them.
In such conventional lever switch, an example of use in changeover of washer motor and wiper motor is explained by referring to FIG. 7 to FIG. 10.
FIG. 7 is an essential sectional view of a conventional lever switch, and FIG. 8 is its perspective exploded view. As shown in FIG. 8, a coil spring 2 and a pin 3 are inserted into an engaging hole 1A formed at the front side of a first end of an operation lever (OL) 1. Further, a cylindrical bump 1B and a through-hole 1C are provided at both sides of the first end.
The OL 1 is mounted on a slider 4 so as to be rotatable in the vertical direction. For this mounting, a shaft 5 is inserted into the through-hole 1C of the OL 1 and a through-hole 4C of the slider 4. The position of the OL 1 in the longitudinal direction is determined as a pin 7 inserted into an engaging hole 4D of the slider 4 together with a coil spring 6 presses a detent plate 8.
A case 9 having a support hole 9A is disposed above the slider 4, and a cover 10 having a support hole 10A, and guide holes 10B, 10C is disposed beneath the slider 4. A shaft 4A projecting to the upper side and a shaft 4B projecting to the lower side of the slider 4 are fitted respectively to the support hole 9A and support hole 10A. By this fitting, the slider 4 is held so as to be rotatable in the longitudinal direction.
A contact piece holder 11 is disposed between the slider 4 and the cover 10. Two holding parts 11A and 11B are formed at the lower side of the contact piece holder 11, and a pair of arms 11D having slant holes 11C are provided at the upper side. As shown in FIG. 7, the arm 11D is contained inside the slider 4, and the bump 1B of the OL 1 is inserted into the slant hole 11C.
At the lower side of the holding part 11A of the contact piece holder 11, a columnar part of a slider 13 holding a cantilever type contact piece 12 is fitted. At the lower side of the holding part 11B, a columnar part of a slider 15 holding a cantilever type contact piece 14 is fitted. Further, contacts 12A, 12B of the contact piece 12 are composed to contact with fixed contacts 16A, 16B for changing over the washer motors formed on a switch substrate 16. Contacts 14A, 14B, 14C of the contact piece 14 are composed to contact with fixed contacts 16C, 16D, 16E, 16F, 16G for changing over the wiper motors formed on the same switch substrate 16. These fixed contacts are connected to the electronic control circuit (not shown) of the vehicle through lead wires 17.
In this configuration, the OL 1 can be manipulated in both vertical direction and longitudinal direction as shown in FIG. 8. FIG. 8 shows an example of operation of the OL 1. For example, when the second end of the OL 1 is manipulated in the vertical direction, the washer motor is turned on and off, and when the second end of the OL 1 is manipulated in the longitudinal direction, the wiper moves according to the manipulation position of the OL 1.
First, when manipulating the OL 1 from the OFF position 100 to the WASH position 104 in the direction of arrow 102 (upward direction), the action of each part until the washer motor is turned on is explained below.
When the OL 1 is manipulated from the OFF position 100 to the WASH position 104 in the direction of arrow 102,
1) The bump 1B of the OL 1 swings in the lower direction around the shaft 5 as a fulcrum of the OL 1,
2) The contact piece holder 11 having the bump 1B into the slant hole 11C moves in the left direction,
3) The slider 13 fitted to the lower side of the holder 11 also moves in the left direction as the columnar part of the slider 13 is guided into the guide hole 10B of the cover 10,
4) The contact piece 12 held at the lower side of the slider 13 moves from the position shown in the layout diagram of the contact piece in FIG. 9A to the position shown in FIG. 9B,
5) The contacts 12A, 12B contact with the fixed contacts 16A, 16B,
6) The fixed contact 16A and fixed contact 16B conduct with each other through the contact piece 12, and
7) The washer motor is turned on by this conduction.
Next, an example of manipulating the second end of the OL 1 in the longitudinal direction is explained below. When the OL 1 is moved from the OFF position 200 to the INT position 202, the wiper operates intermittently. When the OL 1 is moved to the LO position 204, the wiper operates at low speed, and when moved to the HI position 206, the wiper operates at high speed. The operation of the wiper by moving the OL 1 to each position is explained below.
When the second end of the OL 1 is moved from the OFF position 200 in the direction of arrow 208 (forward direction),
1) The slider 4 swings in the rear direction around the shafts 4A, 4B held by the support hole 9A of the case 9 and the support hole 10A of the cover 10,
2) The contact piece holder 11 inserting and holding the slider 4 also moves in the rear direction, and the slider 15 fitted to its lower side moves the columnar part in the rear direction as being guided by the guide hole 10C of the cover 10,
3) The contact piece 14 held at the lower side of the slider 15 moves from the position shown in the contact piece layout in FIG. 10A to the position shown in FIG. 10B,
4) The contacts 14B, 14C contact with the fixed contacts 16D, 16G,
5) The fixed contact 16D and fixed contact 16G conduct through the contact piece 14, and
6) The wiper motor is changed over to the INT mode by this conduction.
When the OL 1 is further manipulated in the forward direction,
7) At the LO position 204 shown in FIG. 10C, the fixed contact 16E and fixed contact 16G conduct through the contact piece 14,
8) At the HI position 206 shown in FIG. 10D, the fixed contact 16F and fixed contact 16G conduct through the contact piece 14, and
9) The wiper motor is changed over at each position by this conduction.
The current flowing at the time of manipulation of washer motor and wiper motor is explained below.
The current changed over by the contact piece 12 for manipulating the washer motor is a micro-current region of about several mA for operating the microcomputer. Accordingly, the thickness of the contact piece 12 may be thin. The contacting pressure of the contact piece 12 and fixed contact may be set small because the current is small. However, in order to operate the wiper motor, the current to be changed over by the contact piece 14 is the sum of the operating current of the microcomputer and the current flowing in the relay for operating and driving the wiper motor. The total current is turned on and off by the contact piece 14 and the fixed contact for operation of the wiper motor. When turning on and off the current, arc discharge takes place between the contact piece 14 and fixed contact. When an arc is generated, the contact portions of the contact piece 14 and fixed contact are consumed. The current generating the arc at the on/off time is called medium current herein. Therefore, in order to withstand this medium current, the material of the contact piece 14 must be thick enough, and the contact pressure of the contact piece 14 and fixed contact must be also set higher.
In the conventional lever switch, however, aside from the contact piece 12 for changing over the small current of the microcomputer, the contact piece 14 differing in the plate thickness and contact pressure for changing over the medium current of the relay are also required. Hitherto, therefore, the contact piece 12 and contact piece 14 were different ones. As a result, the number of parts for composing the lever switch is large and the structure of the lever switch is complicated.
The present invention solves the problems of the prior art, and it is hence an object thereof to present a lever switch capable of changing over the small current and medium current by one contact piece, small in the number of parts, and easy to assemble, and a complex switch using the same.
The lever switch of the present invention comprises:
a. an operation lever to be manipulated in plural directions,
b. a contact piece holder moving parallel in plural directions by the manipulation of this lever,
c. a contact piece of a cross elastic metal thin plate held in the contact piece holder by fitting an engaging hole of its middle part with a protrusion at the lower side of the contact piece holder, and
d. a switch board forming plural fixed contacts elastically contacting with each contact of the contact piece on the upper side.
In this configuration, the contact piece has at least a first contact and a second contact at different positions in the longitudinal direction of each one of arms extending in four directions.
The first contact and second contact formed on each arm are disposed at different positions in the longitudinal direction, and when changing over the medium current, the contact (first contact) contacting first with the fixed contact is consumed by arc discharge. However, the contact (second contact) contacting later with the fixed contact is not consumed because arc discharge does not take place. As a result, the contact between the second contact and the fixed contact is stable for long period. Therefore, the lever switch of the present invention can change over small current and medium current by one contact piece, and the number of parts is smaller and the assembling is easy.